Electron beam tubes



Dec. 6, 1955 Filed March 22, 1951 J. T. WALLMARK ELECTRON BEAM TUBES 3 Sheets-Sheet l INVENTOR Jabg fl Vallmark 4M4, qfid ORNEY D 6, 1955 J. T. WALLMARK ELECTRON BEAM TUBES 3 Sheets-Sheet 3 Filed March 22 1951 OUTPUT lNPt/T 1 450 M M75 Patented Dec. 6, 1955 ELECTRON BEAM TUBES John T. Wallmark, Bromma,

Sweden, assign'or to Radio Corporation of America,

This invention relates to electron beam tubes, and more particularly to curved beam tubes and methods of operating such tubes.

This application is a continuation-in-part of my copending application Serial No. 64,618, filed December 10, 1948, assigned to the same assignee, now abandoned.

In a curved beam type tube a beam of electrons travels a curved path from the beam producing electrodes to an anode or collector electrode. The curved path is usually produced by impelling the electrons into a transverse electric field. It has been proposed in the past to vary the deflecting field by varying the voltage between the transverse field producing electrodes, thereby causing the electron beam to strike in greater or less proportion upon the electron receiving electrode. Another manner in which these curved beam tubes have been operated is to cause the curved path to terminate upon a secondary electron emitting electrode, hereinafter called a dynode. The current of the beam is then varied to vary the number of electrons striking the dynode, thereby producing a variation in the electron flow to a collecting electrode or anode adjacent to the dynode to cause a variation in signal output. Further electron multiplication is sometimes employed.

It is an object of my invention to provide a radically new and improved method of operation of a curved beam tube.

It is still another object of the invention to provide a novel and improved curved beam tube.

It is another object of my invention to provide a curved beam tube having a higher transconductance value for a given current than prior curved beam type tubes.

It is a further object of the invention to provide a method of operating a curved beam type tube to produce a higher transconductance value than may be obtained with the known methods of operating such type tubes.

A still further object of my invention is to improve the signal-to-noise ratio of curved beam type tubes by operating them in an improved manner.

A still further object of the invention is to provide a novel curved beam tube having an improved signal-to noise ratio and a high ratio of transconductance to capacitance so as to provide improved amplification over wide bandwidths.

In conventional electron tubes, e. g. as used for amplification, there are several methods of controlling the electron current to an output anode. In one of these, a control grid or other foraminous electrode is interposed in an electron beam so that variations of grid potential control the current density and total current passing through it. In another method, the electron'beam is passed through a transverse electric field, as produced by deflection plates, for example, so as to change the beam path in such a way that variations of deflection electrode potential cause more or less electrons to pass an intercepting electrode located at one side of the beam path. In both cases, therefore, means are provided whereby the total current in an electron beam beyond a certain point in the electron tube is controlled.

In accordance with the present invention, use is made of a new effect wherein, it is found that, if an electron beam is caused to follow a curved path in a manner later to be described, the curvature of this path is altered when the total current in the electron beam is changed. Thus, any conventional control means of varying the total electron current may be used to interdependently change the electron current and the electron paths and, by use of an intercepting electrode (which would be the second intercepting electrode if the initial variation of current were due to passage beyond a first intercepting electrode), the change in the beam paths may be utilized to change a second time the amount of current reaching the output electrode. In other words, one may apply a small change in potential to a control electrode system which produces a first change in total electron current. This first change in current can, by the principles of the present invention, cause a change in electron path which, in turn, Will cause a second and further change in electron current to the output electrode. 'Thus the initial small change in potential on a conventional control electrode system can be made to produce an increased or augmented control action on the final electron stream in excess of the control action of the conventional system itself. In this way the operating method of the present invention leads to extremely effective amplification, When incorporated in an amplifier tube, or to extremely eifective control of output electron current in any tube to which it is applied. In its ultimate effect, the method of the present invention can cause increased change in output current for a given control potential similar to the use of a secondaryemission electron multiplier. in distinction to the electron multiplier, however, the augmented control action is not accomplished by a multiplication of the current which, as is well known, leads to increased fluctuation noise and power dissipation. Furthermore, as Will be shown, the method of the present invention can be combined with a secondary-emission multiplier so as to achieve still greater control action and lead to a tube perform ance not attained in the prior art.

Throughout the specification and claims, the term beam current (or current of the beam) refers to the total electron current in the beam beyond the control grid or other beam current control electrode normally positioned near the cathode, as distinguished from the electron current (a fraction of the total beam current) reaching a particular output electrode positioned in the beam path.

In accordance with the invention, a curved beam tube is operated by producing a primary beam of electrons and then varying the total current of the primary beam thereby to cause deflection of the beam from one collector electrode to another. It is preferable according to the invention to adjust the quiescent electrode voltage values so that substantially half the beam is received by one collector electrode. With such an adjustment, and particularly with certain novel features of tube construction disclosed herein, a small signal may be applied to a conventional control electrode to initially control the beam current. I have found that, when the signal is so applied to vary the current in the beam of electrons, there results a change in the electron beam path due to the change in space charge. This resultant change in beam path was unknown before my discovery thereof. When the beam is so deflected by this change in space charge, it may be deflected between two collector electrodes so as to cause a second and augmented variation of electron current to each of these electrodes. The effect of such deflection may be greatly heightened as hereinbefore mentioned, and in accordance with a further feature of the invention, when a secondary-emission electrode, hereafter called a dynode, is employed as a collector electrode, the incremental change in the number of electrons received by the dynode caused by the resultant deflection can be made to either aid or counteract the incremental change in the number of electrons reaching the dynode because of the initial beam current change. Further more, I have devised novel curved beam type tubes to take full advantage of the deflection effect pointed out above when operated in accordance with the novel teachings of the invention. In some cases, the tube operated in accordance with the invention may be of the type having a simple focusing or reflecting electrode structure. In other cases, it may be of the type employing a dynode, an anode, a shielding electrode interposed between the dynode and anode, a reflecting electrode, and an electron-beamproducing structure comprising a cathode, a control grid, and a screen grid.

The foregoing objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in connection with the accompanying drawing in which like members refer to identical parts, and in which:

Figs. 1 through 5 are diagrams and graphs which will be referred to in the explanation of the invention;

Fig. 6 is a cross-sectional view of a known curved beam tube of the orbital beam type illustrating beam paths which result when the tube is operated in accordance with the method of my invention;

Fig. 7 is a cross-sectional view of a novel curved beam tube devised according to the invention to take further advantage of the deflection effect pointed out hereinabove and utilizing a dynode, and further showing a circuit diagram schematically illustrating a typical operating circuit.

Fig. 8 is a cross-sectional view of still another novel curved beam tube devised to take advantage of the deflection effect mentioned above but without a dynode, and also showing a circuit diagram schematically illustrating a typical circuit for operation;

Fig. 9 is a cross-sectional view of another curved beam type tube adapted to be operated in accordance with the principles of the invention;

Fig. 10 is a view similar to Fig. 9 of another embodiment of the invention wherein deflecting plates are used to initially control the beam current rather than using a control grid; and

Fig. 11 is a perspective view of another embodiment of the invention adapted to be used as a mixer tube.

The invention can be best understood by reference to the simple case of a parallel plane structure. For an exact analysis it is necessary to consider planes of infinite extent. In Fig. 1, consider a flow of electrons from a source (not shown) and passing through a planar grid electrode G at an acute angle thereto with a velocity vo. corresponding to the positive potential VG of electrode G with respect to the source, toward a planar reflecting electrode R parallel to G. The velocity vo is made up of a component vG perpendicular to the planes of G and R and a component v"o parallel thereto. If the reflector R is at a potential Va which is negative with respect to the grid G by an amount equivalent to the component v'o of vo which is perpendicular to G and R, the electrons will just graze R, being turned around at the surface thereof where a virtual cathode is formed. After grazing R at some point P, the electrons will return to G at a distance X from the point of origin on G. The trajectory a with point P0 and distance X0 illustrates the path for negligible space charge. R for negligible space charge is shown by the slope of the straight solid line b in Fig. 2,'in which potential V is plotted vertically against the distance G--R between the planes. Line b corresponds to zero or very low electron current. The perpendicular component v G is reduced uniformly between G and R.

Due 'to the space charge in the electron stream, the

The constant electric field between G and Cir actual electric field between G and R will not be constant, because the potential will be depressed as shown by the dotted curves c and d, which represent the computed potential distribution for two diiferent electron currents. Curve d is the potential distribution for current is, which may be defined as the space-charge-limited current for a diode with the spacing and potentials of the electrodes G and R. Under the conditions of Fig. 2, is is that current which will cause the electric field strength to be just reduced to zero at R. Curve 0 corresponds to a beam current less than is. It will be noted that for the dotted curves the electric field, measured by the slope of the curve, is greater near G (field E1) and smaller near R (field E2) than the constant electric field for the space charge free case, curve 12. The greater electric field strength in the initial portion of the space GR enhances the reduction of the perpendicular velocity component vc and forces each electron to complete its path with reduced velocity, and hence increases the total transit time of each electron traveling from G to R and back to G in Fig. 1. Since the parallel component vG of electron velocity remains constant regardless of space charge eifects in the ideal case considered, the displacement X is directly proportional to the transit time. Since the position of the virtual cathode remains at R (for electron currents equal to or less than is) the effect of space charge depression of potential between G and R is to cause each electron to be turned back in the plane of the virtual cathode at R, the same as without space charge, but at a different point P1 displaced to the right from P0 in Fig. l, and return to G at a distance X1 from the point of origin on G greater than X0, as indicated by the dotted trajectory c in Fig. 1.

Fig. 3 shows the variation of beam displacement X with beam current i from zero current up to the space charge limited value is, for the ideal, parallel plane case considered above, in relative units. Values of 0', the relative electric field strength at R compared to the space charge free value, are indicated at selected points apong the curve. Fig. 3 shows that the beam displacement X increases per cent as the current i increases from zero to the value is. The slope of this curve is an indication of the extra transconductance that theoretically can be obtained by space charge deflection.

Now consider the general case with the reflector at a potential negative relative to Va. One possibility is to keep the space charge free electric field constant. This can be done by moving the reflector to any distance farther away from G and giving it an appropriate negative potential VR', as shown at R in Fig. 4. The potential distribution b between G and R for zero beam current and for the conditions chosen in Fig. 4 is the same as in Fig. 2, with an extension below the VB. value. A virtual cathode is formed at V, in the plane where the reflector was located in Fig. 2. A very low current beam would follow the same trajectory as a in Fig. 1, being turned back at P0 in the plane of V.

When the beam current is increased, the electric field strength at V tends to decrease. However, the potential at the virtual cathode cannot fall below the value Vn, consequently, a new equilibrium is set up with the virtual cathode shifted to a new position V closer to G. The potential distribution for a selected value of beam current is shown by the dotted curve 0' in Fig. 4. The electric field strength in the space V'-R' is constant, as shown by the straight dotted line, since there is no electron penetration beyond'V' where the beam is turned back. For a given current, the approach of V toward G reduces the beam displacement by reducing the arc height of the dotted curvee of Fig. 1. Therefore, as the distance G-R is increased and Va is made correspondingly more negative, the increase in beam displacement becomes less and less, eventually falling below the space charge free value, at which time the relative beam displacement X/Xo becomes less than unity, for very negative VR.

The effect of making R negative on the relative beam conductive to producing such displacement.

.5 displacement is shown in .Fig. 5, where A is the ratio of the potential diflerence between G and .R to :the potential VG. As shown, the negative effect of space charge depression on beam displacement dominates at high values of A.

The right hand part of Fig. 5, at relativebeam currents 1, shows the'efrect of increasing the beam currents above the space charge saturation value, is. The effect of this increase, in the geometry of, Fig. 2, is to shift the virtual cathode away from R toward G. This reduces the beam displacement, in a manner somewhat similar to increasing 7\ for a particular beam current as indicated in Fig. 5. In this region, the slopes of the curves are entirely negative, approaching zero for very large beam currents. If the space-charge-free electric field is changed, as by changing VG and keeping the distance GR and the reflector potential Vn constant, the only eflect is to change the value of is which, for a given beam current, will change the relative beam current i/is. Changing the distance G.R while keeping VG and VR constant has the same eflect.

In the above analysis it was assumed that the electrons leave G with velocities corresponding to the potential VG, which would require zero emission velocity from the electron source. Due to the random distribution of emission velocities at the source, to make R slightly negative relative to VR. to prevent collection of fast electrons, and hence, it would not be possible to realize the optimum beam displacement indicated by the curve for \='1 of Fig. in a practical device. The best displacement attainable may correspond to operation on the curve for ,\=1.0025, for example.

The simple parallel planes of infinite extent are, of course, impossible to achieve. The phenomena of beam displacement due to space charge depression was dis covered experimentally during the operation of a conventional orbital beam tube under special conditions he xplanation of space charge deflection given above in connection with Figs. 1-5 would apply qualitatively to the geometry of the orbital beam tube, although a rigorous analysis of this geometry would be much more complex.

Space charge deflection maybe utilized in curved-beam tubes, such as orbital beam tubes, for example, to dis place the beam either more or less, as desired, depending on the conditions of operation chosen. If it is desired to increase the displacement with increasing beam current, A should be as near unity as possible and thecontrol grid of the tube should be biased so that the maximumbeam current does not exceed the value is for the particular tube. On the other hand, to'decrease the displacement with increasing beam current, the beam current should be greater than is, that is i/ i5 1, or A should be very large.

The invention will now be described as embodied in several practical tube structures illustrated in Figs. 6 through 11. In the conventional orbital beam tube shown in Fig. 6, an evacuated envelope 10 encloses the electrodes of the tube comprising a cylindrical reflecting electrode 12, a V-shaped dynode 14, an anode 16, a shielding electrode 18, and a screen grid 2%) surrounding a control grid 22 which in turn surrounds a flat cathode 24. The plane of the cathode is normal to that of the shielding electrode 18 which is interposed between the cathode and grids, and the dynode and anode. The anode 16 is located between the dynode 14 and the shielding electrode 18. The electrode 18 functions also as a field electrode. This type of tube is normally operated with the reflecting electrode 12 maintained at or near cathode potential and the electrode 18 at a higher positive potential, thus setting up between these two electrodesa transverse electric field. This field deflects the beam, causing it to follow a curved path, intermediate the field electrodes 12 and 18, to the dynode .14. As stated above, it has been proposed to vary the deflectingfield, by varyit would be necessary.

a enas-s ing the voltage between the field-producing electrodes, to cause the beam to strike in greater or lesser proportion upon the electron receiving electrode. The tube is operated below cathode saturation so that as the voltage on control grid 22 becomes more positive with respect to the voltage on the cathode 24, the current of the electron beam emanating therefrom increases. In accordance with the understanding of the prior art, such an increase in control grid voltage would cause an increased number of primary electrons to strike the anode 15 and dynode 14, but in like proportions as before. However, I have found that this expected result does not always occur. On the contrary, if the electron beam follows a curved path, unsymmetrical with respect to the deflecting electric field between the reflecting electrode 12 and the electrode 18 in its initial stages of escape from the grid structures and in. the first portion of electron travel which approaches closer to reflecting electrode 12, an incremental increase in control grid voltage, .which increases the beam current, causes a change in the efiective transverse electric field along the electron path, due to the increased space charge in that region, which displaces the beam farther away from the point of origin. Conversely, with an incremental decrease in control grid voltage, the resulting decrease in beam current causes a change in the eflFective transverse electric field along the path, which causes the beam to be displaced less than with the higher current, as illustrated in Fig. 6 by the solid lines 26. The solid lines 26 indicate in a qualitative way the paths of electrons emanating from the cathode and grid assembly when the current of the electron beam is decreased, whereas the dotted lines 28 indicate qualitatively the paths which occur upon an incremental increase in current. The expectations from the prior art would lead one to believe that the paths would not be changed by changes in beam current only. The eflect of increasing the control grid potential to increase the current of the beam and simultaneously deflect the beam away from the focusing or reflecting electrode 12, is that, not only is the number of electrons striking the dynode in a given time increased by reason of increased current, but the number is further increased by the resulting change in the electron paths. Consequently, the overall transconductance between control grid 22 and anode 16, as measured by the ratio of the increments of anode current to control grid voltage, is much greater than the transconductance which can be secured by operating the tube in accordance with the prior art.

Referring now more particularly to Fig. 7 which is a cross-sectional view of a novel electron discharge device devised particularly to take advantage of the space charge deflection efifect, the envelope and electrode structure may be the same as that of the conventional discharge device of Fig. 6 except for the addition of a field electrode 3%} interposed between the shielding electrode 18 and anode 16, the electrode 30 being in this instance concave with respect to the latter.

One function of the field electrode 36 is to maintain the field conditions in the upper half of the tube of Fig. 7, as viewed therein, B, substantially independent of space charge effects by creating a strong electric field thereby to draw the electrons rapidly out of that area. As a consequence, the space charge effect with increased beam current and consequent change of the path of electron travel is more marked in the lower portion of the tube, as viewed in Fig. 7, particularly in the area roughly designated A. The total result is that the end point of travel of the electron beam is displaced a greater amount with incremental changes in initial beam current. The electrode 30 also serves as an intercepting electrode. A minor portion of the primary electrons not intercepted by field electrode 30 may strike the anode directly, rather than the dynode, al-

though this efliect is not important,

particularly in the area roughly designated be the same as shown in the tube in Figs. 6 and 7.

The striking advantages of operating in accordance with the invention will bev apparent from the fact that a tube of the type illustrated in Fig. 7 and operated in the manner described herein Will give transconductance values as high as milliamperes per volt to theoutput anode for a current of only 3 milliamperes thereto. Even more remarkable is that, due to the utilization of space charge deflection, the output signal-to-noise ratio of this tube has been found to be comparable to that of the best existing pentode type tubes. It will be noted that in the device of Fig. 7 operated by the method of the invention, as in the described operation of the tube of Fig. 6, the eifect of increased beam current is to increase the deflection to the dynode, and vice versa, which is a factor in the outstanding excellence of this tube.

Fig. 7 illustrates a typical circuit which may be used in the operation of the tube. A direct current power source 46 is connected to the various electrodes. The negative terminal of the power source is grounded, and biasing is obtained by connecting cathode 24 through a resistor capacitor combination 42 to ground. Another source of direct current voltage 44 connected with its positive terminal to ground may also be used for control grid bias, the negative terminal being connected through the source of input signal 46 to control grid 22. Either or both means of bias may be employed. The reflector electrode 12 is connected to ground. The positive terminal of direct current voltage source is connected through a load 48 from which is taken the output from anode 16. The dynode 14, field electrode 39, screen grid 20 and shielding electrode 18 are connected to variable points on source 40 intermediate the negative and positive terminals, possible voltage values to ground being indicated on Figure 7, and are by-passed to ground for voltages of signal frequency by capacitors 50, 52, 5d and 55, respectively, as shown. Good results have also been obtained with electrode 18 at zero potential and electrode 30 as high as 500 volts.

The quiescent voltage values of the various electrodes are so adjusted that with no signal the electron beam follows a path shown by the solid lines, and is substantially equally divided between field electrode 30 and dynode 14. It will be understood that all electrons escaping the dynode 14, including the primary electrons and the secondary electrons, are collected by anode 1.6, Whereas all electrons striking the field electrode 30 are captured thereby. When the beam current is increased, as by a signal applied by input t6, the electron beam will be deflected, as a result of space charge deflection, toward a position, such as that indicated by the dotted lines, where the entire beam is received by the dynode 14. The beam is turned back a short distance from the surface of the reflecting electrode 12 because the potential difference between the screen grid 24) and the reflector 12 is greater than the voltage corresponding to the component of electron velocity perpendicular to the reflector 12. This corresponds to operation with A somewhat greater than unity in Fig. 5.

Referring now more particularly to Fig. 8, the electron discharge device there shown has no dynode but is adapted to operate in accordance with the invention as a curved beam tube without the use of a dynode. The electrode assembly of the cathode, control grid and screen grid may The envelope 1% reflecting electrode 12 and shielding electrode 18 may also be the same as those shown in the other tubes. A U-shaped field electrode and a planar anode 62 are provided. The field electrode 6t is concave to anode 62 which is substantially coplanar with the line of symmetry of electrode 60 and is partially inserted into the mouth of the U. Anode 62 is oriented substantially normal to shielding electrode 18 with U-shaped electrode 66 interposed between the anode and the shielding electrode. As in .the circuit of Fig. 7, bias may be supplied by either or both of a cathode resistor-capacitor combination various electrodes so that the electron beam,

42 and-a source of control grid bias 44. The input signal is applied between the source 44 andcontrol grid 22. Quiescent voltage values are applied to the electrodes so that in the absence of signal the electron beam is divided between electrode 60 and anode 62 receiving about onehalf the beam. Upon application of the signal to the control grid, the current of the electron beam is varied and simultaneously the beam termination is shifted back and forth between electrode 60 and anode 62. Anode 62 receives substantially all of the electrons at times when the beam current is greatest as illustrated by the dotted lines in the figure. When the beam current is least then substantially all of the electrons are received by the field electrode 60. Output is taken from an output or load circuit 48 connected to anode 62. With the tube and circuit of Fig. 8, operated in the novel manner described herein, ratios of transconductance to current as high as 4 have been obtained.

Fig. 9 shows a curved beam type tube having an envelope 70, a set of electron beam producing electrodes including an electron source 72, a control grid 74, and a screen grid 76, and further electrodes comprising a field electrode 78 and an anode 80. There is also an arcuately shaped electrode 82 which reflects the electrons in their orbital path. Quiescent voltage values are applied to the in the absence of signal, as indicated by the dotted lines 84, terminates at an intercepting edge 78' of electrode 78, in such a manner that the beam is substantially bisected by this edge of the electrode, half the beam being received by anode and half being collected by field electrode 78. It now a signal voltage is applied to control grid 74, as indicated by the generator 86, the current of the electron beam 84 varies. It will be observed that the field electrode 78. anode $0, reflector electrode 82, and screen electrode 76 are maintained at fixed potentials, their voltages being maintained quiescent. As the current of beam 84 is varied, the trajectory or curved path of the beam of electrons is changed, due to the changed space charge condition in the electric field space created between the fixed voltage electrodes 78 and 82, which field space is not varied in field conditions other than by the variation in space charge caused by the changed current of the primary beam of electrons, so that the beam 84 is deflected between electrodes 78 and anode 80. It will be clear that a load 88 may be connected to the anode 80 and the output taken therefrom.

Fig. 10 is a cross-sectional view of a tube similar to the one illustrated in Fig. 9, except for the gun structure and the means for varying the current of the electron beam 95 In the tube of Fig. 10, deflecting plates 92 are provided to which the signal is applied and by which means the electron beam is swung slightly normal to the plane of the view of Fig. 10 to be intercepted by an edge 78 of electrode 78 to vary the beam current in the region beyond the edge 7 8". The beam 90 is deflected first, up and down as viewed in Fig. 10, by a signal on deflecting plates 92 impressed by a generator 86. In the region beyond the edge 78" and between the electrodes 78 and 82, the beam 90 is deflected a second time, by the changed space charge condition resulting from the change beam current, in a direction transverse to the first deflection. This second beam deflection results in either more or less electrons being picked up by the anode 80, because of the space charge deflection parallel to the plane in which the view of Fig. 10 is taken. Accordingly, the output may be taken, as before, from a load 88 connected to anode 86.

In the mixer tube shown in perspective in Fig. 11, the various electrodes have the same general configuration as the corresponding electrodes in Fig. 7. However, the anode is divided centrally to form two spaced parts 16 and 16" connected in push pull to an output I. F. transformer T. In order to deflect the beam from the cathode 24 up and down along the length of the dynode 14, the field electrode 3t), or the shield electrode 18, or both, may be digreases .vided centrally, as shown, and an pscillator voltage source is connected to the two parts-thereof. Alternatively, end plates 90 and 91 may be provided to deflect the beam along the dynode. The signal voltage is applied to the grid 22. Quiescent voltages may be applied to the various electrodes as indicated on Fig. 11. In operation, the beam is deflected by the signal by space charge deflection, between the dynode 14 and field electrode 30, and simultaneously deflected by the oscillator voltage along the dynode 14, to produce an I. F. output to transformer T.

It will be apparent from the foregoing that l have originated a method of operating a conventional curved beam type tube in such a way as to increase the effective transconductance' value beyond transconductance values for tubes operated in conventional fashion. It will also be apparent that such operation provides an improved signal-to-noise ratio since the increased transconductance may be achieved without increase in'electron current and the consequent increase in noise. I have also devised novel curved beam type tubes. Moreover, I have devised improved beam type tube which, When operated in accordance with the novel method of the invention to take full advantage of the principles thereof, give still higher values of transconductance and have improved signal-tonoise ratios.

What 1 claim is:

1. An electrical system comprising electrode means for producing a beam of electrons along a predetermined curved path, means for interdependently varying the current of the electron beam and deflecting the beam from said path, and an electron receiving electrode positioned in said path to receive one proportion of said beam for maximum current and a lesser proportion of said beam for minimum current. a

2. An electrical system comprising electrode means for producing a beam of electrons along a predetermined curved path, said electrode means including means for producing a fixed electric field unsymmetrical with respect to said beam path and through which said beam is directed, an electron receiving electrode, and means for interdependently changing the current of the electron beam and deflecting the beam from said path, said electron receiv ing electrode being positioned in said path to receive one proportion of said beam for maximum current and a lesser proportion of said beam for minimum current.

3. An electrical system comprising electrode means for producing a beam of electrons along a predetermined curved path, said electrode means including means for producing a fixed electric field unsymmetrical with respect to said beam path and through which said beam is directed,

an electron receiving electrode, and single means for interdependently varying the current of the electron beam and deflecting the beam from said path, said electron receiving electrode being positioned in said path to receive one proportion of said beam for maximum current and a lesser proportion of said beam for minimum current.

4. An electrical system comprising electrode means for producing a beam of electrons along a predetermined curved path, a beam receiving electrode disposed partly in said path to receive a portion of said beam in the absence of signal, and means for 'interdependently varying the current of said beam and deflecting said beam from said path in accordance with a signal with said electron receiving electrode receiving one proportion of said beam for maximum current and a lesser .proportion of said beam for minimumcurrent.

5. An electrical system comprising means for producing a beam of electrons, means for subjecting said beam to a fixed transverse electric field for causing said beam to follow a predeterminedcurved path, an electrode disposed partly in said path for receiving a predetermined portion of said beam in the absence of signal, and means for changing the current of said beam through said field and thereby deflecting said beam from said curved path 10 in accordance with a signal, whereby .said portion of the beam received by said electrode is changed.

6. The method of operating an electron discharge device comprising the steps of producing a primary beam of electrons, directing said beam in a curved beam path to be received in part in the absenceof signal by an electron receiving electrode, and interdependently varying the current of said beam and said beam path in accordance with a signal with said electron receiving electrode receiving one proportion of said beam for maximum current and a lesser proportion of said beam for minimum current.

7. The method of varying the curved path of a beam of electrons in an electron discharge device, comprising the steps of directing a beam of electrons through a fixed electric field having components transverse to the direction of said beam to give the beam a curved path, and interdependently varying the current of said beam and said curved path.

8. The method of operating a curved beam electron tube comprising the .steps of producing a primary beam of electrons, varying the electron current of said primary beam, and passing said primary beam through a fixed electric deflecting field produced by electrodes having fixed voltages thereon in which field the deflection of said beam is varied by and in accordance with the beam current variations.

9. The method of operating a curved beam electron tube having two electron receiving electrodes comprising the steps of producing a primary beam of electrons, passing said primary field to be received upon and divided in predetermined ratio between said electrodes, changing the electron current of said beam and thereby changing the deflection of the beam in said field, to change the proportion of said beam received by each of said electrodes.

10. The method of operating a curved beam electron tube having electron receiving electrodes, field electrodes,

electrodes.

electrodes for producing a primary beam of electrons including a control electrode to control the electron current of said primary beam of electrons and a screen electrode, comprising the steps of producing a fixed electric field by applying fixed voltages on'said field electrodes, directing said beam in a curved path through said field and toward one of said electron receiving electrodes, and varying the curvature of said curved path by varying the beam current, to vary the proportion of said electrons striking said one electrode.

11. The method of operating a curved beam electron tube having field electrodes and electron receiving electrodes one being a dynode, comprising the steps of producing an electric field between said field electrodes by applying voltages thereto, maintaining said voltages quiescent, producing a beam of electrons having a curved path through said field and terminating with substantially half the beam received by said dynode, and varying said curved path by increasing and decreasing the current of said beam thereby respectively to increase and decrease the proportion of said beam received by said dynode.

12. The method of operating a curved beam electron tube having electron receiving electrodes and field electrodes, comprising the steps of producing an electric field between said field electrodes by applying voltages thereto, maintaining said voltages quiescent, producing a beam of electrons having a curved path through said field terminating at said electron receiving electrodes, and varying said curved path by varying the current of said beam thereby to vary the proportion of said beam received by said 13. The method of operating an orbital beam tube having a first set of electrodes to produce a beam of elecbeam through a fixed electric deflecting 11 r V producing a primary beam of electrons from said cathode having said beam termingating to be received one-half by said anode, maintaining said reflecting electrode at a fixed potential, and applying a signal to said control electrode to increase and decrease the current of said electron beam and also thereby varying the orbit of said electrons by said increase and decrease.

14. An electron discharge device of the curved beam type comprising a first set of electrodes to produce a beam of electrons including a cathode and a control electrode and a screen grid adjacent said cathode, an anode electrode spaced from said first set of electrodes, a dynode electrode arranged on the side of said anode electrode remote from said cathode and closely adjacent to said anode electrode, a shielding electrode interposed between said dynode and anode electrodes and said first set of electrodes, a field electrode interposed between said anode electrode and said shielding electrode, and a reflecting electrode surrounding the other electrodes.

15. An electron discharge device of the curved beam type comprising a first set of electrodes to produce a beam of electrons and including a substantially planar cathode and a control electrode adjacent thereto, electrodes comprising an anode disposed substantially normal to the plane of said cathode, a dynode substantially symmetrical to the plane of said cathode and arranged on the opposite side of said anode from said cathode and convex to said anode, a shielding electrode interposed between said anode and said first set of electrodes, a field electrode interposed between said anode and said shielding electrode and a reflecting electrode surrounding the other electrodes.

16. An electron discharge device of the curved beam type comprising a first set of electrodes to produce a beam of electrons and including a substantially planar cathode and a control electrode adjacent thereto, an anode electrode disposed substantially normal to the plane of said cathode, a dynode electrode substantially symmetrical to the plane of said cathode and arranged on the opposite side of said anode electrode from said cathode, a shielding electrode interposed between said anode electrode and said first set of electrodes, a field electrode interposed between said anode and shielding electrodes, and a reflector surrounding all said other electrodes.

17. The combination comprising an electron discharge device of the curved beam type having electron receiving electrodes, means to produce a beam of electrons along a predetermined curved path, and field electrodes adjacent said path, means to maintain fixed voltages on said field electrodes to produce a fixed electric field transverse to said beam whereby said path is curved and said beam is received in predetermined proportion by one of said electron receiving electrodes in the absence of beam current variation, and means for varying said curved path by varying the current of said beam whereby a greater proportion of said beam is received by said one electron-receiving electrode for maximum current and a lesser proportion of said beam is received by said one electronreceiving electrode for minimum current than said predetermined proportion.

18. The combination comprising an electron discharge device of the curved beam type having a first set of electrodes including a cathode and a control electrode adjacent thereto to produce a beam of electrons, a second set of electrodes including an anode, a shielding electrode interposed between said first and second sets of electrodes, and a reflecting electrode surrounding said first and second sets of electrodes and said shielding electrode, means for maintaining quiescent voltages on said electrodes to cause said beam of electrons to follow a predetermined curved path from said first to said second sets of electrodes around said shielding electrode, and means to apply a signal to said control electrode to increase and decrease the electron of said beam and thereby simultaneously cause beam deflection from said curved path to produce a signal on said anode. I Y r 19. The combination comprising an electron discharge device comprising aset of beam producing electrodes including a cathode and a control electrode adjacent thereto, an electron receiving electrode, a shielding electrode interposed between said electron receiving electrode and said setof electrodes; a field electrode between said electron receiving and shielding electrodes and a reflecting electrode surrounding all the other electrodes, means for applying voltages to said electrodes to produce a high electron accelerating field between said anode and said reflecting electrode and a low electron accelerating field between said beam producing electrodes and said reflecting electrode, means to apply a signal between said cathode and control electrode to vary the beam current and means to maintain quiescent the voltages applied to all of the other electrodes.

20. The combination claimed in claim 19, said electron receiving electrode being a dynode arranged to receive an increased portion of the beam with increased beam current.

21. An electron discharge device comprising a set of beam producing electrodes having a substantially planar cathode, a control electrode adjacent thereto, and a screen electrode adjacent said control electrode, an anode substantially coplanar with said cathode, a shielding electrode interposed between said anode and said set of beam producing electrodes, a field electrode between said anode and said shielding electrode, and a reflecting electrode surrounding all of the other electrodes.

22. An electron discharge device comprising a set of beam producing electrodes having a substantially planar cathode, a control grid surrounding said cathode and a screen grid surrounding said control grid, an anode substantially coplanar with said cathode, a shielding electrode interposed between said anode and said set of beam producing electrodes, a field electrode concave to said anode interposed between said anode and said shielding electrode, and a reflecting electrode surrounding all of the other electrodes.

23. The method of variably deflecting a beam of electrons, comprising the steps of directing a beam of electrons in a given initial direction, subjecting said beam to a fixed transverse electric field thereby causing said beam to follow a curved path, and deflecting said beam from said curved path by changing the current of said beam.

24. An electrical system comprising means for producing and directing a beam of electrons along a curved path and including a plurality of electrodes and means for applying fixed potentials to said electrodes to cause said electrons to traverse a predetermined curved path for a given beam current, an electron-receiving electrode positioned in said predetermined path, and means for interdependently changing the current of said beam and deflecting said beam from said predetermined path, to change the proportion of said beam received by said electron-receiving electrode.

25. An electrical system comprising means for producing and directing a beam of electrons along a curved path and including a plurality of electrodes and means for applying fixed potentials to said electrodes to establish a predetermined electric field along said path for a given beam current, an electron-receiving electrode positioned in said path, and means for interdependently changing the current of said beam and the intensity of said electric field, to deflect said beam relative to said electron receiving electrode.

26. An electrical system including an electron discharge devicerof the curved beam type comprising a first set of electrodes to produce a beam of electrons including a cathode anda control electrode adjacent to said cathode, a dynode electrode spaced from said first set of electrodes, an anode electrode adjacent to said dynode electrode in position to receive secondary electrons emitted thereby, a field electrode adjacent to said anode electrode in position to prevent primary electrons from said cathode from reaching said anode electrode, a shielding electrode interposed between said cathode and said dynode, anode and field electrodes, and a reflecting electrode surrounding the other electrodes, means for maintaining said anode electrode at a high positive potential relative to said cathode and reflector electrodes, and means for maintaining said field, dynode and shield electrodes at successively lower positive potentials in the order named.

27. An electrical system comprising electrode means for producing a beam of electrons along a predetermined curved path, an electron receiving electrode in said path, and means for interdependently changing the current of the electron beam and deflecting the beam from said path, to change the proportion of the beam received by said electrode.

28. An electrical system comprising electrode means for producing a beam of electrons along a predetermined curved path, a dynode positioned in said path, an anode adjacent to said dynode for collecting secondary electrons emitted thereby, and means for interdependently varying the current of the electron beam and deflecting the beam from said path and said dynode, to vary the proportion of the beam received by said dynode.

29; An electrical system according to claim 28, wherein said anode is divided into two separate parts, further including means for independently deflecting the electron beam along said dynode to produce a difiierential electron current to said anode parts.

30. An electron discharge device of the curved beam type, comprising a first set of electrodes to produce a beam of electrons including a cathode and a control electrode adjacent to said cathode, an anode electrode spaced from said first set of electrodes, a dynode electrode arranged on the side of said anode electrode remote from said cathode and closely adjacent thereto, a field electrode adjacent to said anode electrode in position to prevent primary electrons from said cathode from reaching said anode electrode, a shielding electrode interposed between said cathode and said dynode, anode and field electrodes, and a reflecting electrode surrounding the other electrodes, wherein said anode electrode is divided into two separate parts, and one of said field electrodes and said shielding electrode are similarly divided into two separate parts to permit the application of a deflecting voltage thereto for deflecting the beam relative to said anode parts.

31. An electron discharge device of the curved beam other electrodes, wherein said anode electrode is divided into two separate parts and said device further includes a deflecting plate located adjacent to each end of said electrodes for deflecting the beam relative to said anode parts.

32. An electron discharge device of the curved beam type comprising a first set of electrodes to produce a beam of electrons including a cathode and a control electrode adjacent said cathode, an anode electrode spaced from said first set of electrodes, afield electrode interposed between said cathode and said anode electrode, a reflecting electrode surrounding the other electrodes, said anode being divided into two separate parts, and electrode means for independently deflecting the beam' rela tive to said anode parts.

References Cited in the file of this patent UNITED STATES PATENTS 2,138,928 Klemperer Dec. 6, 1938 2,173,267 Strutt et al. Sept. 19, 1939 2,254,096 Thompson Aug. 26, 1941 2,272,165 Varian et al. Feb. 3, 1942 2,272,232 Wagner Feb. 10, 1942 2,293,417 Thompson Aug. 18, 1942 2,293,418 Wagner Aug. 18, 1942 2,470,732 Visscher May 17, 1949 

